The present invention relates to intravascular catheters, and more particularly to a catheter having metallic reinforcing braiding configured to provide the catheter with radiopaque properties and/or kink resistance.
Several types of catheters are utilized for intravascular treatment. Examples of intravascular catheters include guide catheters, angioplasty catheters, stent delivery devices, angiographic catheters, neuro catheters, and the like.
Guiding catheters are commonly used during coronary angioplasty procedures to aid in delivering a balloon catheter or other interventional medical devices to a treatment site in a coronary vessel. In a routine coronary angioplasty procedure, a guiding catheter is introduced into a peripheral artery and advanced over a guidewire through the aorta until the distal end of the guiding catheter is engaged with the appropriate coronary ostium. Next a balloon dilatation catheter is introduced over the guidewire and through the guiding catheter. The guidewire is advanced past the distal end of the guiding catheter within the lumen of the diseased vessel and manipulated across the region of the stenosis. The balloon dilatation catheter is then advanced past the distal end of the guiding catheter over the guidewire until the balloon is positioned across the stenotic lesion. After the balloon is inflated to dilate the blood vessel in the region of the stenotic lesion, the guidewire, balloon dilatation catheter and guiding catheter are withdrawn.
Guiding catheters typically have preformed bends formed along their distal portion to facilitate placement of the distal end of the guiding catheter into the ostium of a particular coronary artery of a patient. In order to function efficiently, guiding catheters should have a relatively stiff main body portion and soft distal tip. The stiff main body portion gives the guiding catheter sufficient "pushability" and "torqueability" to allow the guiding catheter to be inserted percutaneously into a peripheral artery, moved and rotated in the vasculature to position the distal end of the catheter at the desired site adjacent to a particular coronary artery. However, the distal portion should have sufficient flexibility so that it can track over a guidewire and be maneuvered through a tortuous path to the treatment site. In addition, a soft distal tip at the very distal end of the catheter should be used to minimize the risk of causing trauma to a blood vessel while the guiding catheter is being moved through the vasculature to the proper position. Such a soft tip is described in U.S. Pat. No. 4,531,943. In additon, the inner surface of the guiding catheter should be lubricious to facilitate movement of guidewires, balloon catheters and other interventional medical devices therethrough.
Angiographic catheters can be used in evaluating the progress of coronary artery disease in patients. Angiography procedures are used to view the patency of selected blood vessels. In carrying out this procedure, a diagnostic catheter having a desired distal end curvature configuration may be advanced over a guide wire through the vascular system of the patient until the distal end of the catheter is steered into the particular coronary artery to be examined.
A non-limiting example of an angioplasty catheter is found in U.S. Pat. No. 4,646,742. A non-limiting example of a stent deployment device is found in U.S. Pat. No. 5,201,757.
In that the path taken by intravascular catheters is sometimes tortuous, it is important that an intravascular catheter can be steered by torquing its proximal hub and that the torque be transmitted to the distal end in a smooth, controllable fashion. Moreover, the catheter should have sufficient strength in the longitudinal direction so as not to kink or fold as it is advanced through the vascular system. It should also possess a lubricious core lumen to facilitate passage of a guidewire or possibly another catheter or device therethrough.
It is also a desirable feature of certain intravascular catheters that it possess a relatively large lumen to allow fluids, such as radiopaque contrast fluid to be injected therethrough and out the distal end so that the area of the vascular system under investigation can be viewed fluoroscopically.
It is also a desirable feature of certain intravascular catheters that it possess radiopaque and/or kink resistance qualities.
The desirable properties of a catheter having a relatively small O.D. and a relatively large I.D. dictates a relatively thin wall. To maintain the desired torqueability and pushability characteristics of a thin wall catheter calls for considerable ingenuity in the formulation of the materials employed and the constructional techniques utilized.